when you meet with some people from other countries, you can practise that.

Are you still a students?If you are ,if ;you want to practice your oral English you can join some Enghish corner to practice; if you already work ,such as me ,maybe your work language is Enghish ,you should speak Enghish all the day ,at that time you have no choice.In a word ,i want to say , oral Enghish is quite important when you get to work,so learn it well when you are in campus.

This question is so CUTE, that I can't give a sarcastic answer. Anyway, I will add this advice: Non-native speakers should avoid cursing. It usually sounds too unnatural.

by oral, do you mean casual English & slangs? if so, you should use casual/oral English with friends, family, co-workers, classmates, people of the same generation, etc etc。 就算用 "你" 或者 "您”。 obviously, at a job interview, you'll want to use formal English - without sounding pompous though.

Well, whenever you like it (as well as using any other language) As long as you find someone to talk in english [2]